#define _CRT_SECURE_NO_WARNINGS

//https://leetcode.cn/problems/string-to-url-lcci/
class Solution {
public:
    string replaceSpaces(string S, int length) {
        string S1("");
        for (int i = 0; i < length; i++)
        {
            if ()
            {
                S.swap()
            }
        }
        return S1;
    }
};


//https://leetcode.cn/problems/add-strings/
class Solution {
public:
    string addStrings(string num1, string num2) {
        int end1 = num1.size() - 1;
        int end2 = num2.size() - 1;
        string str;
        str.reserve(max(num1.size(), num2.size()) + 1);
        int carry = 0;
        while (end1 >= 0 || end2 >= 0)
        {
            int val1 = end1 >= 0 ? num1[end1] - '0' : 0;
            int val2 = end2 >= 0 ? num2[end2] - '0' : 0;

            int ret = val1 + val2 + carry;
            carry = ret / 10;
            ret %= 10;

            str += ('0' + ret);
            end1--;
            end2--;
        }
        if (carry == 1)
            str += '1';
        reverse(str.begin(), str.end());
        return str;
    }
};